RPMA - SPMA Series

SPMA Series: Modules to 3VA


  • Any Synchro, or AC Sin/Cos Inputs. 4.5VA @ 400Hz., and 1.5VA @ 60Hz.
  • Models Trouble Free: Isolated, Wire and Run Design.
  • Ultra-High Efficiency
  • Low Distortion
  • Self-Powered off the AC Reference Input
  • Internal Cool Running AC-Pulsating Supplies
  • Very Low Loss & Heat / Power Dissipation Packaged as 2.6 x 3.1 x .82"H Module
  • Simple Bulk-Head / Backplane Mount High
  • Resistance to Shock & Vibration
  • High Reliability Throughout Implementation
  • No External Power Supplies Required!
  • No External Transformers Required: 60Hz. too.
  • Virtually Indestructible Units: Transformer Isolation to 500VDC  
  • Short Circuit Proof Outputs with internal: Current Limiting, Thermal Shutdown
  • Over-Voltage Transient Protection. 
  • Resolver to Synchro Conversion
  • Synchro to Resolver Conversion w/Power


The SPMA/RPMA Series are low cost solid state synchro and resolver buffer amplifiers, isolators and format converters packaged in industry standard 2.6 x 3.1" modules for printed circuit card mount.

The SPMA/RPMA series provide continuous realtime outputs with high-accuracy, infinite resolution, and without discontinuity. They may be used in real-time applications to buffer and isolate synchro and resolver signals, and as synchro repeaters; to assure non-interaction between differing target subsystems with respect to signal loading, backfed electrical noise, grounding schemes, circulating currents, differing signal potentials between systems, and immunity from ground loops. This is especially important on systems employing computer monitoring and control apparatus on the signals involved, to assure that there is no path to ground (even high impedence) being the most common source of electrical noise in non-isolated systems.

Any 3 wire synchro or 4 wire resolver signal input can be provided and converted or level shifted to any synchro or resolver output format and voltage, providing the same frequency reference source may be used. Simple 26:115V step up or step down transformers can be provided for reference voltage adaption if required.

The SPMA/RPMA series are also ideally suited for use as high accuracy resolver and synchro translators, for adapting 26/11.8V verses 115/90V or even 2V signals; and synchro verses resolver formatted signals between systems anticipating differing signal levels or formats from the field sensors actually being employed. This is very common on various aircraft and gyro related simulators, test apparatus, and subsystems.

The inputs to these converters are available in either low cost Solid State verses internally Transformer Isolated Input models. Both model types feature very high impedence inputs to assure they do not load the source signals typically feeding other devices in a system. Transformer Isolated Input units feature internal micro-transformers to assure that the field signal inputs preserve channel to channel isolation on the field signals coming in, and input channel to power supply isolation. This assures the user that everything is isolated and that by adding new apparatus, they are not connecting new undesirable ground paths into the existing apparatus.

Power input is +/-15VDC and +/-12V powered models are available. The user is cautioned to insure the power supplies feature foldback current limmiting to tolerate the in rush turn-on surges of the class AB hybrid power amplifiers typically employed.

Standard models feature 1.5VA output drive on +/-15V powered models and 1.2VA on +/-12VDC powered models, and model selections for driving up to 5VA loads are made available. All models feature internal aluminum plate heat sinks, thermal, overload and transient protection, and short circuit protected outputs. Additionally; transformer isolated outputs are standard on all models, providing an inductive coupling to the ouputs more typical of the synchro/resolver sensor itself. The transformer coupled outputs accomodate larger loads without compromising the ratio accuracy similar to a synchro itself driving the load.

The SPMA/RPMA series are available in commercial, industrial and Military grade extended temperature range models, and are fully encapsulated for high resistance to shock and vibration.


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